Claims
- 1. An internal combustion engine, comprising:
a cylinder block including a cylinder therein and having a piston reciprocally disposed within said cylinder, said piston operably engaged with a crankshaft; a camshaft in timed driven relationship with said crankshaft; at least one intake valve assembly reciprocally driven by said camshaft; at least one exhaust valve assembly reciprocally driven by said camshaft; and a vacuum release mechanism, comprising:
a vacuum release member attached to said camshaft and centrifugally moveable between first and second positions, said vacuum release member including a vacuum release cam extending therefrom, said vacuum release cam in lifting engagement with one of said valve assemblies in said first position during a portion of a power stroke of said piston to relieve vacuum forces opposing said power stroke, said vacuum release cam disposed out of engagement with said one of said valve assemblies in said second position.
- 2. The internal combustion engine of claim 1, wherein said vacuum release member additionally includes a compression release cam extending therefrom, said compression release cam in lifting engagement with one of said valve assemblies in said first position during a portion of a compression stroke of said piston to relieve compression forces opposing said compression stroke, said compression release cam disposed out of engagement with said one of said valve assemblies in said second position.
- 3. The internal combustion engine of claim 1, wherein said vacuum release member comprises a yoke member pivotally attached to said camshaft, said yoke member pivotable about an axis extending substantially transverse to said camshaft.
- 4. The internal combustion engine of claim 3, wherein said pivot axis comprises a pivot pin extending through said camshaft and attached to said vacuum release member.
- 5. The internal combustion engine of claim 3, wherein said yoke member includes a pair of arms disposed on opposite sides of said camshaft, said arms connected to a central portion from which said vacuum release cam extends.
- 6. The internal combustion engine of claim 5, wherein said pair of arms extend obliquely to said camshaft in said first position, and extend substantially perpendicularly to said camshaft in said second position.
- 7. The internal combustion engine of claim 5, wherein said pair of arms extend substantially parallel to said camshaft in said first position, and extend obliquely to said camshaft in said second position.
- 8. The internal combustion engine of claim 1, wherein said camshaft includes a cam lobe reciprocally driving said exhaust valve assembly, said cam lobe including a recess therein into which said vacuum release cam is disposed in said second position.
- 9. An internal combustion engine, comprising:
a cylinder block including a cylinder therein and having a piston reciprocally disposed within said cylinder, said piston operably engaged with a crankshaft; a camshaft in timed driven relationship with said crankshaft; at least one intake valve assembly reciprocally driven by said camshaft; at least one exhaust valve assembly reciprocally driven by said camshaft; and a compression and vacuum release mechanism, comprising:
a compression and vacuum release member attached to said camshaft and centrifugally moveable between first and second positions, said compression and vacuum release member including a compression release cam and a vacuum release cam extending therefrom, said compression and vacuum release cams respectively in lifting engagement with one of said valve assemblies in said first position during a portion of a compression and a portion of a power stroke of said piston to relieve compression and vacuum forces respectively opposing said compression and said power strokes, said compression and vacuum release cams disposed out of engagement with said one of said valve assemblies in said second position.
- 10. The internal combustion engine of claim 9, wherein said compression and vacuum release member is pivotally attached to said camshaft about an axis extending substantially transverse to said camshaft.
- 11. The internal combustion engine of claim 10, wherein said pivot axis comprises a pivot pin extending through said camshaft and attached to said compression and vacuum release member.
- 12. The internal combustion engine of claim 9, wherein said compression and vacuum release member comprises a yoke member including a pair of arms disposed on opposite sides of said camshaft, said arms connected to a central portion from which said compression and vacuum release cams extend.
- 13. The internal combustion engine of claim 9, wherein said camshaft includes a cam lobe reciprocatingly driving said exhaust valve assembly, said cam lobe including a pair of recesses therein into which said compression and vacuum release cams are respectively disposed in said second position.
- 14. The internal combustion engine of claim 12, wherein said pair of arms extend substantially oblique to said camshaft in said first position, and extend substantially perpendicular to said camshaft in said second position.
- 15. The internal combustion engine of claim 12, wherein said pair of arms extend substantially parallel to said camshaft in said first position, and extend substantially oblique to said camshaft in said second position.
- 16. An internal combustion engine, comprising:
a cylinder block including a cylinder therein and having a piston reciprocally disposed within said cylinder, said piston operably engaged with a crankshaft; a camshaft in timed driven relationship with said crankshaft; at least one intake valve assembly reciprocally driven by said camshaft; at least one exhaust valve assembly reciprocally driven by said camshaft; and a compression and vacuum release mechanism, comprising:
a centrifugally actuated common yoke member moveably attached to said camshaft between a first position corresponding to a cranking speed of said engine and a second position corresponding to a running speed of said engine; a compression release cam extending from said yoke member and in lifting engagement with one of said valve assemblies in said second position during a portion of a compression stroke of said piston to relieve compressive forces opposing said compression stroke; and a vacuum release cam extending from said yoke member and in lifting engagement with said one of said valve assemblies in said first position during a portion of a power stroke of said piston to relieve vacuum forces opposing said power stroke; said compression and vacuum release cams disposed out of lifting engagement with said one of said valve assemblies in said second position.
- 17. The internal combustion engine of claim 16, wherein said yoke member is pivotally mounted to said camshaft by a pivot pin extending substantially transversely through said camshaft.
- 18. The internal combustion engine of claim 16, wherein said yoke member includes a pair of flyweights disposed on opposite sides of said camshaft, said flyweights connected to a central portion from which said compression and vacuum release cams extend.
- 19. The internal combustion engine of claim 18, wherein said pair of flyweights extend obliquely to said camshaft in said first position, and extend substantially perpendicularly to said camshaft in said second position.
- 20. The internal combustion engine of claim 18, wherein said pair of flyweights extend substantially parallel to said camshaft in said first position, and extend substantially obliquely to said camshaft in said second position.
- 21. The internal combustion engine of claim 16, wherein said camshaft includes a cam lobe reciprocatingly driving said exhaust valve assembly, said cam lobe including a pair of recesses therein into which said compression and vacuum release cams are respectively disposed in said second position.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Serial No. 60/231,818, entitled “MECHANICAL COMPRESSION AND VACUUM RELEASE”, filed on Sep. 11, 2000.
Provisional Applications (1)
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Number |
Date |
Country |
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60231818 |
Sep 2000 |
US |